Ethers of polyalkyl or polyalkenyl N-hydroxyalkyl succinimides and fuel compositions containing the same

ABSTRACT

Ethers of polyalkyl or polyalkenyl N-hydroxyalkyl succinimides having the formula:                    
     or a fuel soluble salt thereof; wherein 
     R is a polyalkyl or polyalkenyl group having an average molecular weight in the range of about 450 to about 5,000; 
     n is an integer from 2 to 5; and Z is a moiety selected from the group consisting of                    
      wherein R 1  is a hydroxy, nitro, cyano or —(CH 2 ) x— NR 3 R 4 , wherein R 3  and R 4  are independently hydrogen or lower alkyl of 1 to 6 carbon atoms and x is 0 or 1; and R 2  is hydrogen, hydroxy, nitro, cyano or —(CH 2 ) y—NR   5 R 6 , wherein R 5  and R 6  are independently hydrogen or lower alkyl of 1 to 6 carbon atoms and y is 0 or 1. The compounds of formula I are useful as fuel additives for the prevention and control of engine deposits.

This application is a divisional application of Ser. No. 09/141,633,filed Aug. 28, 1998, now U.S. Pat. No. 6,114,542.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to ethers of polyalkyl or polyalkenylN-hydroxyalkyl succinimides and derivatives thereof. In a furtheraspect, this invention relates to the use of these compounds in fuelcompositions to prevent and control engine deposits.

2. Description of the Related Art

It is well known that automobile engines tend to form deposits on thesurface of engine components, such as carburetor ports, throttle bodies,fuel injectors, intake ports and intake valves, due to the oxidation andpolymerization of hydrocarbon fuel. These deposits, even when present inrelatively minor amounts, often cause noticeable driveability problems,such as stalling and poor acceleration. Moreover, engine deposits cansignificantly increase an automobile's fuel consumption and productionof exhaust pollutants. Therefore, the development of effective fuelengine deposits when used in fuel compositions. U.S. Pat. No. 5,393,309,issued Feb. 28, 1995 to R. E. Cherpeck, discloses a fuel additivecomposition comprising (a) a polyisobutenyl succinimide derived fromethylenediamine or diethylenetriamine, wherein the polyisobutenyl grouphas an average molecular weight of about 1200 to 1500 and (b) anonvolatile paraffinic or naphthenic carrier oil, or a mixture thereof.

Similarly, U.S. Pat. No. 5,620,486, issued Apr. 15, 1997 to R. E.Cherpeck, discloses fuel compositions containing hydrocarbyl-substitutedN-aryl succinimides wherein the nitrogen atom on the succinimide issubstituted with a phenyl ring having one or two substituents selectedfrom hydroxy, carboxyl, nitro, amino and alkylamino.

N-Hydroxyalkyl succinimides are also known in the art. For example, U.S.Pat. No. 3,394,144, issued Jul. 23, 1968 to Giles et al., disclosesN-2hydroxyethyl succinimide and N-3-hydroxypropyl succinimide, which areuseful as intermediates in the preparation of substituted anthraquinonedyes for hydrophobic textile materials.

In addition, U.S.S.R. Pat. No. 241,417, published Apr. 18, 1969,discloses beta-succinimidoethyl esters of aryloxyalkanecarboxylic acids,which are prepared by reacting beta-succinimidoethanol witharyloxyalkylcarboxylic acids.

SUMMARY OF THE INVENTION

I have now discovered certain ethers of polyalkyl or polyalkenylN-hydroxyalkyl succinimides which provide excellent control of enginedeposits, especially intake valve deposits, when employed as fueladditives in fuel compositions.

The compounds of the present invention include those having thefollowing formula and fuel soluble salts thereof:

wherein R is a polyalkyl or polyalkenyl group having an averagemolecular weight in the range of about 450 to about 5,000;

n is an integer from 2 to 5; and Z is a moiety selected from the groupconsisting of

 wherein R₁ is hydroxy, nitro, cyano or —(CH₂)_(x)—NR₃R₄, wherein R₃ andR₄ are independently hydrogen or lower alkyl of 1 to 6 carbon atoms andx is 0 or 1; and R₂ is hydrogen, hydroxy, nitro, cyano or—(CH₂)_(y)—NR₅R₆, wherein R₅ and R₆ are independently hydrogen or loweralkyl of 1 to 6 carbon atoms and y is 0 or 1.

The present invention further provides a fuel composition comprising amajor amount of hydrocarbons boiling in the gasoline or diesel range anda deposit-controlling effective amount of a compound of the presentinvention.

The present invention additionally provides a fuel concentratecomprising an inert stable oleophilic organic solvent boiling in therange of from about 150° F. to 400° F. and from about 10 to 70 weightpercent of a compound of the present invention.

Among other factors, the present invention is based on the surprisingdiscovery that certain ethers of polyalkyl or polyalkenyl N-hydroxyalkylsuccinimides provide excellent control of engine deposits, especially onintake valves, when employed as additives in fuel compositions.

DETAILED DESCRIPTION OF THE INVENTION

Based on performance (e.g. deposit control), handling properties andperformance/cost effectiveness, preferred compounds of the invention arethose wherein Z is substituted phenyl, wherein R₁ is nitro, amino,N-alkylamino, or —CH₂NH₂ (aminomethyl). More preferably, R₁ is a nitro,amino or —CH₂NH₂ group. Most preferably, R₁ is an amino or —CH₂NH₂group, especially amino. Preferably, R₂ is hydrogen, hydroxy, nitro oramino. More preferably, R₂ is hydrogen or hydroxy. Most preferably, R₂is hydrogen. Preferably, R is a polyalkyl or polyalkenyl group having anaverage molecular weight in the range of about 500 to 3,000, morepreferably about 700 to 3,000, and most preferably about 900 to 2,500.Preferably, the compound has a combination of preferred substituents.

Preferably, n is an integer of from 2 to 3.

When R₁ and/or R₂ is an N-alkylamino group, the alkyl group of theN-alkylamino moiety preferably contains 1 to 4 carbon atoms. Morepreferably, the N-alkylamino is N-methylamino or N-ethylamino.

Similarly, when R₁ and/or R₂ is an N,N-dialkylamino group, each alkylgroup of the N,N-dialkylamino moiety preferably contains 1 to 4 carbonatoms. More preferably, each alkyl group is either methyl or ethyl. Forexample, particularly preferred N,N-dialkylamino groups areN,N-dimethylamino, N-ethyl-N-methylamino and N,N-diethylamino groups.

A further preferred group of compounds are those wherein Z issubstituted phenyl, wherein R₁ is amino, nitro, or —CH₂NH₂ and R₂ ishydrogen or hydroxy. A particularly preferred group of compounds arethose wherein R₁ is amino, R₂ is hydrogen, R is a polyalkyl orpolyalkenyl group derived from polyisobutene, and n is 2 or 3.

Another preferred group of compounds are those wherein Z is pyridyl orpiperidyl, R is a polyalkyl or polyalkenyl group derived frompolyisobutene, and n is 2 or 3.

It is preferred that the R₁ substituent is located at the meta or, morepreferably, the para position of the phenoxy moiety, i.e., para or metarelative to the ether oxygen. When R₂ is a substituent other thanhydrogen, it is particularly preferred that this R₂ group be in a metaor para position relative to the ether oxygen and in an ortho positionrelative to the R₁ substituent. Further, in general, when R₂ is otherthan hydrogen, it is preferred that one of R₁ or R₂ is located para tothe ether oxygen and the other is located meta to the ether oxygen.

Similarly, when Z is pyridyl or piperidyl, it is preferred that thenitrogen atom in the pyridyl or piperidyl ring is located para or meta,more preferably para, relative to the ether oxygen.

The compounds of the present invention will generally have a sufficientmolecular weight so as to be non-volatile at normal engine intake valveoperating temperatures (about 200° -250° C.). Typically, the molecularweight of the compounds of this invention will range from about 700 toabout 3,500, preferably from about 700 to about 2,500.

Fuel-soluble salts of the compounds of formula I can be readily preparedfor those compounds containing an amino or substituted amino group andsuch salts are contemplated to be useful for preventing or controllingengine deposits. Suitable salts include, for example, those obtained byprotonating the amino moiety with a strong organic acid, such as analkyl- or arylsulfonic acid. Preferred salts are derived fromtoluenesulfonic acid and methanesulfonic acid.

When the R₁ or R₂ substituent is a hydroxy group, suitable salts can beobtained by deprotonation of the hydroxy group with a base. Such saltsinclude salts of alkali metals, alkaline earth metals, ammonium andsubstituted ammonium salts.

Preferred salts of hydroxy-substituted compounds include alkali metal,alkaline earth metal and substituted ammonium salts.

Definitions

As used herein, the following terms have the following meanings unlessexpressly stated to the contrary.

The term “amino” refers to the group: —NH₂.

The term “N-alkylamino” refers to the group: —NHR_(a) wherein R_(a) isan alkyl group.

The term “N,N-dialkylamino” refers to the group: —NR_(b)R_(c), whereinR_(b) and R_(c) are alkyl groups.

The term “alkyl” refers to both straight- and branched-chain alkylgroups.

The term “lower alkyl” refers to alkyl groups having 1 to about 6 carbonatoms and includes primary, secondary and tertiary alkyl groups. Typicallower alkyl groups include, for example, methyl, ethyl, n-propyl,isopropyl, n-butyl, sec-butyl, t-butyl, n-pentyl, n-hexyl and the like.

The term “polyalkyl” or “polyalkenyl” refers to an alkyl or alkenylgroup, respectively, which is generally derived from polyolefins whichare polymers or copolymers of mono-olefins, particularly 1-mono-olefins,such as ethylene, propylene, butylene, and the like. Preferably, themono-olefin employed will have 2 to about 24 carbon atoms, and morepreferably, about 3 to 12 carbon atoms. More preferred mono-olefinsinclude propylene, butylene, particularly isobutylene, 1-octene and1-decene. Polyolefins prepared from such mono-olefins includepolypropylene, polybutene, especially polyisobutene, and thepolyalphaolefins produced from 1-octene and 1-decene.

The term “fuel” or “hydrocarbon fuel” refers to normally liquidhydrocarbons having boiling points in the range of gasoline and dieselfuels.

General Synthetic Procedures

The ethers of this invention may be prepared by the following generalmethods and procedures. It should be appreciated that where typical orpreferred process conditions (e.g., reaction temperatures, times, moleratios of reactants, solvents, pressures, etc.) are given, other processconditions may also be used unless otherwise stated. Optimum reactionconditions may vary with the particular reactants or solvents used, butsuch conditions can be determined by one skilled in the art by routineoptimization procedures.

Those skilled in the art will also recognize that it may be necessary toblock or protect certain functional groups while conducting thefollowing synthetic procedures.

In such cases, the protecting group will serve to protect the functionalgroup from undesired reactions or to block its undesired reaction withother functional groups or with the reagents used to carry out thedesired chemical transformations. The proper choice of a protectinggroup for a particular functional group will be readily apparent to oneskilled in the art. Various protecting groups and their introduction andremoval are described, for example, in T. W. Greene and P. G. M. Wuts,Protective Groups in Organic Synthesis, Second Edition, Wiley, N.Y.,1991, and references cited therein.

In the present synthetic procedures, a hydroxyl group will preferably beprotected, when necessary, as the benzyl or tert-butyidimethylsilylether. Introduction and removal of these protecting groups is welldescribed in the art. Amino groups may also require protection and thismay be accomplished by employing a standard amino protecting group, suchas a benzyloxycarbonyl or a trifluoroacetyl group. Additionally, as willbe discussed in further detail hereinbelow, the aromatic ethers of thisinvention having an amino group on the aromatic moiety will generally beprepared from the corresponding nitro derivative. Accordingly, in manyof the following procedures, a nitro group will serve as a protectinggroup for the amino moiety.

Moreover, the compounds of this invention having a —CH₂NH₂ group on thearomatic moiety will generally be prepared from the corresponding cyanoderivative, —CN. Thus, in many of the following procedures, a cyanogroup will serve as a protecting group for the —CH₂NH₂ moiety.

Synthesis

The ethers of the present invention may be prepared by a process whichinitially involves reaction of a polyalkyl or polyalkenyl succinicanhydride of the formula:

wherein R is as defined herein, with an alkanolamine of the formula:

H₂N—(CH₂)—OH  (III)

wherein n is defined herein, to provide a polyalkyl or polyalkenylN-hydroxyalkyl succinimide of the formula:

wherein R and n are as defined herein.

The polyalkyl or polyalkenyl succinic anhydrides of Formula II aretypically prepared by the reaction of maleic anhydride with the desiredpolyolefin or chlorinated polyolefin, under reaction conditions wellknown in the art. For example, such succinic anhydrides may be preparedby the thermal reaction of a polyolefin and maleic anhydride, asdescribed, for example in U.S. Pat. Nos. 3,3 61,673 and 3,676,089.Alternatively, the substituted succinic anhydrides can be prepared bythe reaction of chlorinated polyolefins with maleic anhydride, asdescribed, for example, in U.S. Pat. No. 3,172,892. A further discussionof hydrocarbyl-substituted succinic anhydrides can be found, forexample, in U.S. Pat. Nos. 5,620,486 and 5,393,309.

Polyalkenyl succinic anhydrides may be converted to polyalkyl succinicanhydrides by using conventional reducing conditions such as catalytichydrogenation. For catalytic hydrogenation, a preferred catalyst ispalladium on carbon. Likewise, polyalkenyl succinimides may be convertedto polyalkyl succinimides using similar reducing conditions.

The polyalkyl or polyalkenyl substituent on the succinic anhydridesemployed in the invention is generally derived from polyolefins whichare polymers or copolymers of mono-olefins, particularly 1-mono-olefins,such as ethylene, propylene, butylene, and the like. Preferably, themono-olefin employed will have 2 to about 24 carbon atoms, and morepreferably, about 3 to 12 carbon atoms. More preferred mono-olefinsinclude propylene, butylene, particularly isobutylene, 1-octene and1-decene. Polyolefins prepared from such mono-olefins includepolypropylene, polybutene, especially polyisobutene, and thepolyalphaolefins produced from 1-octene and 1-decene.

A particularly preferred polyalkyl or polyalkenyl substituent is onederived from polyisobutene.

The preferred polyisobutenes used to prepare the presently employedpolyalkyl or polyalkenyl succinic anhydrides are polyisobutenes whichcomprise at least about 20% of the more reactive methylvinylideneisomer, preferably at least 50% and more preferably at least 70%.Suitable polyisobutenes include those prepared using BF₃ catalysts. Thepreparation of such polyisobutenes in which the methylvinylidene isomercomprises a high percentage of the total composition is described inU.S. Pat. Nos. 4,152,499 and 4,605,808. Examples of suitablepolyisobutenes having a high alkylvinylidene content include Ultravis30, a polyisobutene having a number average molecular weight of about1300 and a methylvinylidene content of about 74%, and Ultravis 10, apolyisobutene having a number average molecular weight of about 950 anda methylvinylidene content of about 76%, both available from BritishPetroleum.

The alkanolamines of Formula III are known compounds which are availablecommercially or can be readily prepared using conventional procedures.Suitable alkanolamines include 2-aminoethanol, 3 -amino-1-propanol,4-amino-1-butanol, and 5-amino-1-pentanol. Preferred alkanolamines are2-aminoethanol and 3 -amino-1-propanol.

The polyalkyl or polyalkenyl succinic anhydride and alkanolamine aregenerally reacted in essentially equivalent amounts at a temperature inthe range of about 100° C. to 200° C., and preferably from about 125° C.to about 175° C. The reaction may take place in the presence or absenceof an inert solvent.

The time of reaction will vary depending on the particular succinicanhydride and alkanolamine reactants, and the reaction temperature.Generally, the reaction time will range from about one hour to about 24hours.hours. At the completion of the reaction, the polyalkyl orpolyalkenyl N-hydroxyalkyl succinimide product is isolated usingconventional techniques.

The reaction of succinic anhydrides with alkanolamines is known in theart and is described, for example, in U.S. Pat. No. 3,394,144.

The polyalkyl or polyalkenyl N-hydroxyalkyl succinimide of formula IV isthen deprotonated with a suitable base to provide the metal salt of theN-hydroxyalkyl succinimide, which is subsequently reacted with asubstituted phenyl halide of formula VI or a pyridyl halide of formulaVII to provide the aromatic ether compounds of formula I. The aromatichalide compounds of formulas VI and VII can be represented as follows:

wherein R₁ and R₂ are as defined herein, and X is a halogen, such asfluoro, chloro, or bromo, and wherein any hydroxy or amino substituenton the substituted phenyl halide of formula VI is preferably protectedwith a suitable protecting group, for example, a benzyl or nitro group,respectively. Moreover, a —CH₂NH₂ substituent on the aromatic ring willpreferably be protected by the use of a cyano group, CN.

Generally, the deprotonation reaction will be effected by contacting thepolyalkyl or polyalkenyl N-hydroxyalkyl succinimide of formula IV with astrong base, such as sodium hydride, potassium hydride, sodium amide,potassium hydroxide, and the like, in an inert solvent, such as toluene,xylene, and the like, under substantially anhydrous conditions at atemperature in the range of about −10° C. to about 120° C. for about0.25 to about 3 hours. This reaction may also be promoted by coppersalts. See, for example, J. Lindley, Tetrahedron, Vol. 40, pp.1433-1456,1984.

The metal salt of the N-hydroxyalkyl succinimide is generally notisolated, but is reacted in situ with about 0.8 to about 2.0 molarequivalents of the substituted and suitably protected phenyl halide offormula VI or pyridyl halide of formula VII. Typically, this reaction isconducted in a substantially anhydrous inert solvent at a temperature inthe range of about 30° C. to about 160° C. for about 0.5 to about 48hours. Suitable solvents for this reaction include toluene, xylene,tetrahydrofuran, and the like. The reaction will generally be conductedat a pressure sufficient to contain the reactants and the solvent,preferably at atmospheric or ambient pressure.

The substituted phenyl halides of formula VI are generally knowncompounds and can be prepared from known compounds using conventionalprocedures or obvious modifications thereof. Representative phenylhalides which may be used as starting materials and, if necessary, whensuitably protected, include, for example, 4-fluoronitrobenzene,4-bromonitrobenzene, 3 -fluoronitrobenzene, 3-bromonitrobenzene,2-hydroxy-4-fluoronitrobenzene, 2-hydroxy-4-bromonitrobenzene,2-nitro-4-fluorophenol, and 2-nitro-4-bromophenol. When the R₁substituent is —CH₂—NR₃R₄, suitable starting materials include, forexample, 4-fluorocyanobenzene, 4-bromocyanobenzene,3-fluorocyanobenzene, and 3-bromocyanobenzene.

Preferred substituted phenyl halides include 4-fluoronitrobenzene,2-hydroxy-4-fluoronitrobenzene, and 4-fluorocyanobenzene.

The pyridyl halides of formula VII are also known compounds and include4-fluoropyridine and 3-fluoropyridine.

When the substituted phenyl halides of formula VI contain a hydroxylgroup, protection of the aromatic hydroxyl groups may be accomplishedusing well-known procedures. The choice of a suitable protecting groupfor a particular hydroxy-substituted phenyl halide will be apparent tothose skilled in the art. Various protecting groups, and theirintroduction and removal, are described, for example, in T. W. Greeneand P. G. M. Wuts, Protective Groups in Organic Synthesis, SecondEdition, Wiley, N.Y., 1991, and references cited therein.

After completion of the etherification reaction, deprotection of thearomatic hydroxyl group can also be accomplished using conventionalprocedures. Appropriate conditions for this deprotection step willdepend upon the protecting group(s) utilized in the synthesis and willbe readily apparent to those skilled in the art. For example, benzylprotecting groups may be removed by hydrogenolysis under 1 to about 4atmospheres of hydrogen in the presence of a catalyst, such as palladiumon carbon. Typically, this deprotection reaction is conducted in aninert solvent, preferably a mixture of ethyl acetate and acetic acid, ata temperature of from about 0° C. to about 40° C. for about 1 to about24 hours.

When the substituted phenyl halides of formula VI have a free aminogroup (—NH₂) on the phenyl moiety, it is generally desirable to employthe corresponding nitro compound (i.e., where R₁ and/or R₂ is a nitrogroup) and then reduce the nitro group to an amino group usingconventional procedures. Aromatic nitro groups may be reduced to aminogroups using a number of procedures that are well known in the art. Forexample, aromatic nitro groups may be reduced under catalytichydrogenation conditions; or by using a reducing metal, such as zinc,tin, iron and the like, in the presence of an acid, such as dilutehydrochloric acid. Generally, reduction of the nitro group by catalytichydrogenation is preferred. Typically, this reaction is conducted usingabout 1 to 4 atmospheres of hydrogen and a platinum or palladiumcatalyst, such as palladium on carbon. The reaction is typically carriedout at a temperature of about 0° C. to about 100° C. for about 1 to 24hours.hours in an inert solvent, such as ethanol, ethyl acetate and thelike. Hydrogenation of aromatic nitro groups is discussed in furtherdetail in, for example, P. N. Rylander, Catalytic Hydrogenation inOrganic Synthesis, pp. 113-137, Academic Press (1979); and OrganicSynthesis, Collective Vol. I, Second Edition, pp. 240-241, John Wiley &Sons, Inc. (1941); and references cited therein.

Likewise, when the substituted phenyl halides of formula VI contain a—CH₂NH₂ group on the phenyl moiety, it is generally desirable to employthe corresponding cyano compounds (i.e., where R₁ and/or R₂ is a —CNgroup), and then reduce the cyano group to a —CH₂NH₂ group usingconventional procedures. Aromatic yano groups may be reduced to —CH₂NH₂groups using procedures well known in the art. For example, aromaticcyano groups may be reduced under catalytic hydrogenation conditionssimilar to those described above for reduction of aromatic nitro groupsto amino groups. Thus, this reaction is typically conducted using about1 to 4 atmospheres of hydrogen and a platinum or palladium catalyst,such as palladium on carbon. Another suitable catalyst is a Lindlarcatalyst, which is palladium on calcium carbonate. The hydrogenation maybe carried out at temperatures of about 0° C. to about 100° C. for about1 to 24 hours in an inert solvent such as ethanol, ethyl acetate, andthe like. Hydrogenation of aromatic cyano groups is further discussed inthe references cited above for reduction of aromatic nitro groups.

In a similar fashion, compounds of formula I wherein the substituent Zis a piperidyl group may be conveniently prepared by first preparing thecorresponding pyridyl compound (i.e., where Z is pyridyl), and thenreducing the pyridyl group to a piperidyl group using conventionalreducing conditions. Hydrogenation of pyridyl groups is discussed infurther detail in, for example, P. N. Rylander, Catalytic Hydrogenationin Organic Synthesis, pp. 213-220, Academic Press (1979); and in M.Hudlicky, Reductions in Organic Chemistry, Second Edition, pp. 69-71,ACS monograph: 188, American Chemical Society (1996); and referencescited therein.

An alternative procedure for preparing the compounds of formula Iinvolves initially deprotonating an alkanolamine of formula III with asuitable base, such as sodium hydride, to form the metal salt of thealkanolamine, and then reacting the metal salt with a substituted phenylhalide of formula VI or a pyridyl halide of formula VII, under reactionconditions as described above, to provide a phenyl or pyridyl ether ofthe alkanolamine of formula III. The phenyl or pyridyl ether of thealkanolamine is then reacted with a polyalkyl or polyalkenyl succinicanhydride of formula II to provide the succinimides of formula I usingthe above reaction conditions for forming succinimides from theanhydride.

Fuel Compositions

The compounds of the present invention are useful as additives inhydrocarbon fuels to prevent and control engine deposits, particularlyintake valve deposits. The proper concentration of additive necessary toachieve the desired deposit control varies depending upon the type offuel employed, the type of engine, and the presence of other fueladditives.

In general, the concentration of the compounds of this invention inhydrocarbon fuel will range from about 50 to about 2500 parts permillion (ppm) by weight, preferably from 75 to 1,000 ppm. When otherdeposit control additives are present, a lesser amount of the presentadditive may be used.

The compounds of the present invention may be formulated as aconcentrate using an inert stable oleophilic (i.e., dissolves ingasoline) organic solvent boiling in the range of about 150° F. to 400°F. (about 65° C. to 205° C.). Preferably, an aliphatic or an aromatichydrocarbon solvent is used, such as benzene, toluene, xylene orhigher-boiling aromatics or aromatic thinners. Aliphatic alcoholscontaining about 3 to 8 carbon atoms, such as isopropanol,isobutylcarbinol, n-butanol and the like, in combination withhydrocarbon solvents are also suitable for use with the presentadditives. In the concentrate, the amount of the additive will generallyrange from about 10 to about 70 weight percent, preferably 10 to 50weight percent, more preferably from 20 to 40 weight percent.

In gasoline fuels, other fuel additives may be employed with theadditives of the present invention, including, for example, oxygenates,such as t-butyl methyl ether, antiknock agents, such asmethylcyclopentadienyl manganese tricarbonyl, and otherdispersants/detergents, such as hydrocarbyl amines, hydrocarbylpoly(oxyalkylene) amines, hydrocarbyl poly(oxyalkylene) aminocarbamates,or succinimides. Additionally, antioxidants, metal deactivators anddemulsifiers.may be present.

In diesel fuels, other well-known additives can be employed, such aspour point depressants, flow improvers, cetane improvers, and the like.

A fuel-soluble, nonvolatile carrier fluid or oil may also be used withthe ethers of this invention. The carrier fluid is a chemically inerthydrocarbon-soluble liquid vehicle which substantially increases thenonvolatile residue (NVR), or solvent-free liquid fraction of the fueladditive composition while not overwhelmingly contributing to octanerequirement increase. The carrier fluid may be a natural or syntheticoil, such as mineral oil, refined petroleum oils, synthetic polyalkanesand alkenes, including hydrogenated and unhydrogenated polyalphaolefins,and synthetic polyoxyalkylene-derived oils, such as those described, forexample, in U.S. Pat. No. 4,191,537 to Lewis, and polyesters, such asthose described, for example, in U.S. Pat. Nos. 3,756,793 to Robinsonand 5,004,478 to Vogel et al., and in European Patent Application Nos.356,726, published Mar. 7, 1990, and 382,159, published Aug. 16, 1990.

These carrier fluids are believed to act as a carrier for the fueladditives of the present invention and to assist in removing andretarding deposits. The carrier fluid may also exhibit synergisticdeposit control properties when used in combination with an ethercompound of this invention.

The carrier fluids are typically employed in amounts ranging from about100 to about 5000 ppm by weight of the hydrocarbon fuel, preferably from400 to 3000 ppm of the fuel. Preferably, the ratio of carrier fluid todeposit control additive will range from about 0.5:1 to about 10:1, morepreferably from 1:1 to 4:1, most preferably about 2:1.

When employed in a fuel concentrate, carrier fluids will generally bepresent in amounts ranging from about 20 to about 60 weight percent,preferably from 30 to 50 weight percent.

PREPARATIONS AND EXAMPLES

A further understanding of the invention can be had in the followingnonlimiting Examples. Wherein unless expressly stated to the contrary,all temperatures and temperature ranges refer to the Centigrade systemand the term “ambient” or “room temperature” refers to about 20° C.-25°C. The term “percent” or “%” refers to weight percent and the term“mole” or “moles” refers to gram moles. The term “equivalent” refers toa quantity of reagent equal in moles, to the moles of the preceding orsucceeding reactant recited in that example in terms of finite moles orfinite weight or volume. Where given, proton-magnetic resonance spectrum(p.m.r. or n.m.r.) were determined at 300 mHz, signals are assigned assinglets (s), broad singlets (bs), doublets (d), double doublets (dd),triplets (t), double triplets (dt), quartets (q), and multiplets (m),and cps refers to cycles per second.

Example 1 Preparation of

To a flask equipped with a magnetic stirrer, reflux condenser,thermocouple, septa and nitrogen inlet was added sodium hydride (4.7grams, 60 weight percent dispersion in mineral oil ) and anhydrousmethyl sulfoxide (50 mL). The contents of the flask were heated to 40°C. for 30 minutes. The solution was cooled to room temperature andethanolamine (6.2 mL) was added. 1-Fluoro-4-nitrobenzene (10.0 mL) wasadded dropwise so that the temperature was approximately 30° C. did notexceed 40° C. The reaction was stirred for 30 minutes, then diluted withdichloromethane (150 mL) and washed with water (3×100 mL). The organiclayer was dried over anhydrous magnesium sulfate, filtered andconcentrated in vacuo to yield 8.4 grams of the desired product as anorange oil.

Example 2 Preparation of

To a flask equipped with a mechanical stirrer, Dean-Stark trap,thermometer, reflux condensor and nitrogen inlet was added 31.2 grams ofpolyisobutenylsuccinic anhydride (0.03 moles, saponificationnumber=77.6, derived from polyisobutene which had an approximatemolecular weight of 950 and a methylvinylidene content of 86%). Theproduct from Example 1 (5.5 grams, 0.03 moles) was added and the mixturewas stirred at room temperature for 30 minutes, 50° C. for 30 minutesand 175° C. for 36 hours to yield a viscous oil after cooling to roomtemperature. The resultant oil were chromatographed on silica geleluting with hexane/ethyl acetate (7:1), followed by hexane/ethylacetate (3.2) and ethyl acetate to yield 25.9 grams of the desiredsuccinimide.

Example 3 Preparation of

A solution of 15.5 grams of the product from Example 2 in 150 mL ofethyl acetate and 100 mL of toluene containing 2.3 grams of 10%palladium on charcoal was hydrogenated at 50 psi for 72 hours on a Parrlow-pressure hydrogenator. Catalyst filtration and removal of thesolvent in vacuo yielded 11.3 grams of the desired aniline as an oil. ¹HNMR (CDCl₃) δ 6.75 (AB quartet, 2H), 6.6 (AB quartet, 2H), 4.05 (t, 2H),3.9 (t, 2H), 3.5 (bs, 2H), 0.7-3.1 (m, 140H).

Example 4 Preparation of

To a flask equipped with a magnetic stirrer, reflux condensor,thermocouple, septa and nitrogen inlet was added sodium hydride (4.7grams, 60 weight percent dispersion in mineral oil ). Ethanolamine (11.2mL) was added and the contents of the flask were stirred at roomtemperature for 30 minutes. 4-Chloropyridine hydrochloride (13.9 gramsdissolved in 109 mL of ethanolamine) was added dropwise and the reactionwas stirred at 100° C. for sixteen hours. The reaction was diluted withtoluene (400 mL), filtered and concentrated in vacuo to yield thedesired product.

Example 5 Preparation of

To a flask equipped with a mechanical stirrer, Dean-Stark trap,thermometer, reflux condenser and nitrogen inlet was added 23.0 grams ofpolyisobutenylsuccinic anhydride (0.03 moles, saponificationnumber=77.6, derived from polyisobutene which had an approximatemolecular weight of 950 and a methylvinylidene content of 86%). Theproduct from Example 4 (4.6 grams, 0.03 moles) was added and the mixturewas stirred at 170° C. for 16 hours to yield a viscous oil after coolingto room temperature. The resultant oil was diluted with hexane (300 mL)and washed with water (3×100 mL) followed by saturated aqeous sodiumchloride (1×100 mL). The organic layer was dried over anhydrousmagnesium sulfate, filtered and concentrated in vacuo to yield thedesired succinimide.

Example 6 Single-Cylinder Engine Test

The test compounds were blended in gasoline and their deposit reducingcapacity determined in an ASTM/CFR single-cylinder engine test.

A Waukesha CFR single-cylinder engine was used. Each run was carried outfor 15 hours, at the end of which time the intake valve was removed,washed with hexane and weighed. The previously determined weight of theclean valve was subtracted from the weight of the value at the end ofthe run. The differences between the two weights is the weight of thedeposit. A lesser amount of deposit indicates a superior additive. Theoperating conditions of the test were as follows: water jackettemperature 200° F.; vacuum of 12 in Hg, air-fuel ratio of 12, ignitionspark timing of 40° BTC; engine speed is 1800 rpm; the crankcase oil isa commercial 30W oil.

The amount of carbonaceous deposit in milligrams on the intake valves isreported for each of the test compounds in Table I.

TABLE I Intake Valve Deposit Weight (in milligrams) Sample¹ Run 1 Run 2Average Base Fuel 365.2 343.1 354.2 Example 3 195.0 — 195.0 ¹At 50 partsper million actives (ppma) and 50 ppm ofα-hydroxy-ω-4-dodecylphenoxypoly(oxypropylene) having an average of12-13 oxypropylene units (prepared essentially as described in Example 6of U.S. Pat. No. 4,160,648) carrier oil.

The base fuel employed in the above single-cylinder engine tests was aregular octane unleaded gasoline containing no fuel detergent. The testcompounds were admixed with the base fuel to give a concentration of 50ppma (parts per million actives) and 50 ppm ofα-hydroxy-δ-4-dodecylphenoxypoly(oxypropylene) having an average of12-13 oxypropylene units (prepared essentially as described in Example 6of U.S. Pat. No. 4,160,648) carrier oil.

The data in Table I illustrates the significant reduction in intakevalve deposits provided by an ether of the present invention (Examples3) compared to the base fuel, even at a very low additive concentration.

What is claim is:
 1. A fuel composition comprising a major amount ofhydrocarbons boiling in the gasoline or diesel range and an effectivedeposit-controlling amount of a compound of the formula:

or a fuel soluble salt thereof; wherein R is a polyalkyl or polyalkenylgroup having an average molecular weight in the range of about 450 toabout 5,000; n is an integer from 2 to 5; and Z is a moiety selectedfrom the group consisting of


2. The fuel composition according to claim 1, wherein Z is pyridyl. 3.The fuel composition according to claim 1, wherein Z is piperidyl. 4.The fuel composition according to claim 1, wherein R is a polyalkyl orpolyalkenyl group having an average molecular weight in the range ofabout 500 to 3,000.
 5. The fuel composition according to claim 4,wherein R is a polyalkyl or polyalkenyl group having an averagemolecular weight in the range of about 700 to 3,000.
 6. The fuelcomposition according to claim 5, wherein R is a polyalkyl orpolyalkenyl group having an average molecular weight in the range ofabout 900 to 2,500.
 7. The fuel composition according to claim 1,wherein R is a polyalkyl or polyalkenyl group derived frompolypropylene, polybutene, or a polyalphaolefin oligomer of 1-octene or1-decene.
 8. The fuel composition according to claim 7, wherein R is apolyalkyl or polyalkenyl group derived from polyisobutene.
 9. The fuelcomposition according to claim 8, wherein the polyisobutene contains atleast about 20% of a methylvinylidene isomer.
 10. The fuel compositionaccording to claim 1, wherein n is 2 or
 3. 11. The fuel compositionaccording to claim 1, wherein Z is pyridyl or piperidyl, R is apolyalkyl or polyalkenyl group derived from polyisobutene, and n is 2 or3.
 12. The fuel composition according to claim 1, wherein thecomposition contains from about 50 to about 2,000 parts per million byweight of said compound.
 13. The fuel composition according to claim 1,where the composition further contains from about 100 to about 5,000parts per million by weight of a fuel-soluble, nonvolatile carrierfluid.
 14. A fuel concentrate comprising an inert stable oleophilicorganic solvent boiling in the range of from about 150° F. to 400° F.and from about 10 to about 70 weight percent of a compound of theformula:

or a fuel soluble salt thereof; wherein R is a polyalkyl or polyalkenylgroup having an average molecular weight in the range of about 450 toabout 5,000; n is an integer from 2 to 5; and Z is a moiety selectedfrom the group consisting of


15. The fuel concentrate according to claim 14, wherein Z is pyridyl.16. The fuel concentrate according to claim 14, wherein Z is piperidyl.17. The fuel concentrate according to claim 14, wherein R is a polyalkylor polyalkenyl group having an average molecular weight in the range ofabout 500 to 3,000.
 18. The fuel concentrate according to claim 17,wherein R is a polyalkyl or polyalkenyl group having an averagemolecular weight in the range of about 700 to 3,000.
 19. The fuelconcentrate according to claim 18, wherein R is a polyalkyl orpolyalkenyl group having an average molecular weight in the range ofabout 900 to 2,500.
 20. The fuel concentrate according to claim 14,wherein R is a polyalkyl or polyalkenyl group derived frompolypropylene, polybutene, or a polyalphaolef in oligomer of 1-octene or1-decene.
 21. The fuel concentrate according to claim 20, wherein R is apolyalkyl or polyalkenyl group derived from polyisobutene.
 22. The fuelconcentrate according to claim 17, wherein the polyisobutene contains atleast about 20% of a methylvinylidene isomer.
 23. The fuel concentrateaccording to claim 14, wherein n is 2 or
 3. 24. The fuel concentrateaccording to claim 14, wherein Z is pyridyl or piperidyl, R is apolyalkyl or polyalkenyl group derived from polyisobutene, and n is 2 or3.
 25. The fuel concentrate according to claim 14, wherein the fuelconcentrate further contains from about 20 to about 60 weight percent ofa fuel-soluble, nonvolatile carrier fluid.
 26. A compound of theformula:

or a fuel soluble salt thereof; wherein R is a polyalkyl or polyalkenylgroup having an average molecular weight in the range of about 450 toabout 5,000; n is an integer from 2 to 5; and Z is a moiety selectedfrom the group consisting of


27. The compound according to claim 26, wherein Z is pyridyl.
 28. Thecompound according to claim 26, wherein Z is piperidyl.
 29. The compoundaccording to claim 26, wherein R is a polyalkyl or polyalkenyl grouphaving an average molecular weight in the range of about 500 to 3,000.30. The compound according to claim 29, wherein R is a polyalkyl orpolyalkenyl group having an average molecular weight in the range ofabout 700 to 3,000.
 31. The compound according to claim 30, wherein R isa polyalkyl or polyalkenyl group having an average molecular weight inthe range of about 900 to 2,500.
 32. The compound according to claim 29,wherein R is a polyalkyl or polyalkenyl group derived frompolypropylene, polybutene, or a polyalphaolefin oligomer of 1-octene or1-decene.
 33. The compound according to claim 32, wherein R is apolyalkyl or polyalkenyl group derived from polyisobutene.
 34. Thecompound according to claim 33, wherein the polyisobutene contains atleast about 20% of a methylvinylidene isomer.
 35. The compound accordingto claim 26, wherein n is 2 or
 3. 36. The compound according to claim26, wherein Z is pyridyl or piperidyl, R is a polyalkyl or polyalkenylgroup derived from polyisobutene, and n is 2 or 3.